Streamer, Jill Evans2022-06-152022-06-152022-06-14vt_gsexam:34737http://hdl.handle.net/10919/110781The human body is a complicated dynamic system that is difficult to model because of the numerous interactions that occur between limbs during various tasks. There are documented movement differences when assessing movement in various populations, for example, joint angle and loading symmetry differences when comparing a clinical and healthy population. Symmetry deficits can impact quality of life and in some cases have been associated with an increase in injury risk. Therefore, it is essential to understand movement and loading symmetry in healthy individuals to facilitate the identification of rehabilitation targets. The purpose of this research was to assess the impact that task type and sex have on movement variability and load symmetry in healthy younger adults. The tasks included in this study represent activities of daily living such as level walking, stair ascent, stair descent and standing up from a chair. A wireless, single-sensor in-shoe force sensor allowed for data collection in a non-laboratory setting so that peak impact force and average loading rate could be evaluated across the different daily tasks. To assess movement variability, the coefficients of variation (CV) were determined for each task. The peak impact force (PIF) did not show a significant interaction between sex and task (p=0.627) or between sexes (p=0.685). The PIF did show significant between-task differences (p < 0.001), where the highest mean CV was observed in the sit-to-stand task and the lowest CV was observed during level walking. The variation between movements could be a result of the differential motor skill required to perform the task. The average loading rate (ALR) did not show a significant interaction between sex and task (p=0.069) or between sexes (p=0.624). The average loading rate showed significant between-task differences (p < 0.001), where the highest mean CV was observed in the sit-to-stand task and the lowest CV was observed during level walking. Based on these results, differences in movement type needs to be considered when evaluating average loading rate. To assess the impact of task type on load symmetry, the absolute symmetry index was calculated for the peak impact force and the average loading rate. For both parameters, only between task differences were identified (p < 0.001) and further analysis showed that sit-to-stand was significantly different from the other three movement tasks. The acceptable threshold for a healthy level of asymmetry has been defined in a clinical population to be less than 10%. Based on a chi square analysis, the 10% threshold accurately represents 95% of the population when used to measure peak impact force in level walking, stair ascent and stair descent. However, when assessing peak impact force symmetry during sit-to-stand or assessing average loading rate symmetry between tasks, the 10% threshold does not consistently represent 95% of the population. These results indicate that a threshold for a healthy symmetry may need to be redefined for bilateral movements and that the symmetry threshold may need to be specific to the outcome measure of interest.ETDenIn CopyrightAsymmetryImpact ForceMovement VariabilityLoading Rateloadsol®Thesis